In split genes, the coding sequences are called exons. Split genes, also known as interrupted genes or split genes, are genes that contain intervening sequences called introns within their coding sequences. These introns are non-coding regions of DNA that do not contribute to the final protein product.

Here is a detailed explanation:

1. Split Genes:
- Split genes are commonly found in eukaryotic organisms, including humans. They are called split genes because their coding sequences are interrupted by non-coding regions or introns.
- The presence of introns in split genes is a characteristic feature that distinguishes them from other types of genes.

2. Coding Sequences:
- Coding sequences in split genes are the regions of DNA that contain the information necessary to produce a functional protein.
- These coding sequences are divided into segments called exons. Exons are the regions of DNA that are transcribed into RNA and eventually translated into protein.
- Exons are the coding regions that contain the information for the amino acid sequence of the protein.

3. Introns:
- Introns, on the other hand, are non-coding regions of DNA that lie between the exons within the split genes.
- Introns do not code for any functional protein product.
- They are transcribed into RNA along with the exons during the process of gene expression but are removed from the RNA molecule during a process called splicing.
- The splicing process involves the removal of introns and the joining together of exons to produce a mature mRNA molecule that can be translated into protein.

4. Importance of Introns:
- Introns play important roles in gene regulation and evolution.
- They can contain regulatory elements that influence the expression of the gene.
- Introns also allow for alternative splicing, which is the process by which different combinations of exons can be joined together to produce different protein isoforms from a single gene.

In conclusion, split genes have coding sequences called exons, which are interrupted by non-coding regions called introns. The exons contain the information for the amino acid sequence of the protein, while the introns are removed during splicing and do not contribute to the final protein product.